Re: [PHP-DEV] Re: Bug #850 Updated: pconnects fail if database has released session From: Andreas Karajannis (Andreas.Karajannis <email protected>)
Date: 10/22/98

> with an odbc datasource. isn't it that all connections are implicit
> network (=remote)
> connections and REMOTE SQL must be started for adabas to function
> properly?
>
> [jakob]
> servernode=styx.courant.de
> serverdb=JAKOB

No, just omit the "servernode" entry. Then you can connect "directly"
(w/o x_server) to a database on the same machine.

>
> in the long run this would eat up too much "persistent" sessions.
> imagine someone running a ten user license ...
>
> btw ... i work with php3 as an apache module. how many persistent
> connections/sessions are established with the database?
>
> does the configuration of apache's spareservers influence the number of
> connections/sessions ? e.g.
>
> ###### httpd.conf ########
> ...
> MinSpareServers 5
> MaxSpareServers 10
> StartServers 5
> ...
> ##########################
>

That's the downside - Theoretically, the number of connections can grow
up to the number set by MaxClients (default: 256). This sets the limit
on the number of simultaneous requests that can be supported (And thus
the number of simultaneous running servers, each of them possibly has a
DB connection opened).

Since the overhead of opening a database connection is relatively low
with Adabas (as compared with e.g. Oracle), there shouldn't be too much
performance loss, if you use odbc_connect() instead of odbc_pconnect().
So you have the lowest possible number of simultaneous db connections
open.

MaxSpareServers controls the number of servers allowed to be idle, e.g.
serving no request. If there are more idle servers, they will be killed
(and their possibly established pconnection gets shutdown).
 
The kernel parameter mentioned is SESSION TIMEOUT.

-Andreas 

-- 
Andreas Karajannis

GMD National Research Center for Information Technology

Schloss Birlinghoven, D-53754 Sankt Augustin

Phone +49 2241 142948

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